Senior Member

I haven't heard "grate" used in reference to teeth, but it doesn't surprise me that someone might use it similarly to "gnash", as a metaphor for the subject's mental state of anguish. Usually in English you will hear "grate" in relation to nerves, rather than teeth -- Management in this company really grates my nerves!

The expression "gnashing of teeth" is mostly used metaphorically, to indicate the subject's anxiety, anguish, etc.

"Grind" is used in reference to teeth when the subject is clenching his jaw and rubbing his teeth across each other. It's a more literal, physical description.

Another related term would be "grit" -- I could tell the way he was gritting his teeth that the student orchestra's playing really grated his nerves!

Senior Member

Gnash is maybe used more to signify greedy eating / biting
eg "gnash down a load of grub" (grub being slang for food)

Grind is often used with drug use or something you do in your sleep.
eg "that was rough speed I was grinding for hours"
eg "your grinding kept me awake all night"

Grate signifies annoyance and is probably how I'd described the recorded works of James Blunt
eg "if you haven't heard the teeth grating artistry of the Back to Bedlam creator in Poland yet - you are quite fortunate."

Gnashing is the most biting related use.
Grinding is the most physical use.
Grating is the most thought/emotion/opinion related use.

Senior Member

Whenever I hear or read the word "gnash" I invariably think of Baba Yaga. If you know who she is you'll immediately understand the image that should appear in your mind when faced with this word. Gnashing is an activity exclusive to teeth. Grinding is applying continuous force(think of a mortar and pestle) to break something down into a minute powdery size. Grinding one's teeth is usually done when the person feels anxiety or nervous. Grating with reference to teeth could probably be interchangeable. Returning to Gnashing this can also be likened to what a monster(like Baba Yaga) does with its teeth to instill fear. Gnashing looks very disgusting and crude while the other two do not necessarily have to be so.

Senior Member

Whenever I hear or read the word "gnash" I invariably think of Baba Yaga. If you know who she is you'll immediately understand the image that should appear in your mind when faced with this word. Gnashing is an activity exclusive to teeth. Grinding is applying continuous force(think of a mortar and pestle) to break something down into a minute powdery size. Grinding one's teeth is usually done when the person feels anxiety or nervous. Grating with reference to teeth could probably be interchangeable. Returning to Gnashing this can also be likened to what a monster(like Baba Yaga) does with its teeth to instill fear. Gnashing looks very disgusting and crude while the other two do not necessarily have to be so.